Anatomical die.



L. M. FARNUM.

ANATOMICAL DIE. APPLICATION FILED JUNE 25.1915.

I Patented Sept. 19,1916.

UNITED STATES PATENT OFFICE.

LEON M. lEAIEtNUlVI, F CHICAGO, ILLINOIS.

ANATOMICAL DIE.

Application filed June 25, 1915.

To all whom it'mag concern Be it known that I, LEON M. FARNUM, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Anatomical Dies, of which the following is a specification.

I11 the formation of metallic crowns for teeth, the practice is to form the end or cusp plate and solder thereto the band which is to incase the tooth. Heretofore the char acter of the dies for forming the cusps has been such that a separate die or matrix has been required for nearly every tooth, for the reason that the cusps made on one of such dies would not fit with bands varying much if any in diameter without producing an improperly shaped crown.

The main objects of this invention, therefore, are to provide an improved form of die for making tooth crowns, whereby the shape of the cusp formed thereon is such as will suit bands of varying diameters, and at the same time facilitate the formation of a more satisfactory marginal ridge at the juncture of such band and cusp plate; and to provide an anvil member having a plurality of dies or matrices of this kind formed therein, these being so selected that a comparatively small number of varying sizes will suit practically all of the conditions met in dentistry.

An illustrative embodiment of this invention is shown in the accompanying drawings, in which:

Figure 1 is a plan view of an anvil member having a plurality of the improved svaging dies formed therein. Fig. 2 is an enlarged fragmentary section of the anvil member taken through one of the dies. Fig. 3 is a sectional view of a cusp plate formed on the die shown in Fig. 2. Fig. l is a sectional detail of the same showing the band soldered thereto. Fig. 5 is a sectional view of the finished crown. Fig. 6 is a sectional view of a cusp plate made on one of the bicuspid dies illustrated in Fig. 1, and afterward bent for use on a bicuspid tooth where the bite is unusually deep. Fig. 7 is a sectional view of a band made to fit said cusp plate. Fig. 8 is a sectional view of the finished crown. Fig. 9 is a sectional view of a cusp made, in accordance with previous practice, for the same kind of a tooth as the cusp shown in Fig. 6. Fig. 10 is a view of a corresponding band. Fig. 11 is a sectional Specification of Letters Patent.

Patented Sept. 19, 1916.

Serial No. 36,374.

formed that the finished crown assumes substantially the natural conditions, that is, having the grooves and fissures in the cusp fit with the projections on the abutting or opposed teeth, so that the same degree of occlusion will be obtained with the crown in position as is found in the natural teeth. Thus, in making the'cusps, the die is used mainly for the purpose of approximating a form which will coact properly with the opposed teeth, and the definite form is afterward completed by taking a bite, that is, placing the crown on the tooth and having the patient force the teeth together as in biting so as to cause the cusp of the crown to' conform more definitely with the shape of the opposed teeth.

In the present invention two difficulties encountered in the former method of forming the cusp and attaching the band have been overcome, namely, the necessity of havmg to provide many different dies in order to closely approximate each of the many variations found in natural teeth, and the fact that the old form of die formed a marginal flange which rendered difficult and unsatisfactory the final formation of the cusp by taking the bite.

In the construction shown in the drawings, the member 1, a heavy bronze or other suitable metal block, has a plurality of matrices or dies 2 formed therein. These matrices are of varying sizes and shapes ranging from the smaller, shown near the center of the block, to the larger ones shown along the edges. The arrangement of the dies or depressions on the block, however, is immaterial. It has heretofore been the practice in this art to use dies in which the depressions correspond exactly to the shapes of the faces of human teeth, and to form them of such depth that the edges of their marginal portions 8.1 will face in the direction of the side walls 9.1 of the band of the tooth-crown which is to be formed, and may be soldered end to end with such edges as illustrated in Figs. 9, 10 and 11. In the herein described improved construction the depressions have the same general appearance, but they are made considerably shallower, somewhat larger in diameter, and their marginal portions are inclined so as to meet the plane of the top face of the die at an acute angle.

The difference between my improved dies and those of usual construction is illustrated in Fig. 2, in which the full line 3 represents the bottom of the depression in a die constructed according to the present invention, and the dotted line 1 represents the usual practice which has heretofore prevailed. It will be noted that the marginal portions 5 of the depression indicated by the full line 3 meet the top surface 6 of the die at an acute angle, approximately 45 degrees, whereas the marginal portions 7 of the depression indicated by the dotted line 1 are substantially perpendicular to the top surface 6. Then a cusp plate 8 (Fig. 3) is formed by my improved die, it will accommodate bands varying considerably in diameter from the diameter of the die depression as will be observed from Figs. 12, 13 and 1%.

In making crowns in accordance with the herein described invention, the first step in forming the cusp 8 is to give it the general shape of the face of the tooth being crowned, 11. e., bicuspid, molar, etc. No attempt is made to have it approximate the depth of the depression which it must have in its final form. The band 9 which is to form the side walls of the crown is made to have a snug fit with the tooth to which it is to be applied. If the tooth being crowned and the opposing teeth have prominent interfitting depressions and projections, such as are found in many bicuspids, the edge of the band which is to be attached to the cusp is cut to have the same contour as the marginal edge of the tooth, as indicated in Fig. 7. The cusp and band are tacked with solder on a lingual where there is contact and placed on the tooth for the purpose of taking a bite. As the teeth are brought together, the projections and depressions on the abutting teeth shape the cusp accordingly. By reason of the cusp and band being attached only at one point, the cusps are readily adjusted, under the pressure, to the proper shape to provide the necessary oc clusion. The crown is then removed and the cusp and band firmly soldered together. hen this is completed, the overhanging edges of the cusp or plate 8 are ground off, leaving a smooth rounded marginal ridge, as illustrated in the figures, which marginal ridge conforms with that of the natural tooth.

It will be seen that by this method of construction, and by reason of the reduced depth of the die and the slope of the marginal portions thereof, the same die may be used for making the cusps for crowns the bands for which Vary widely in shape and diameter as diagrammatically illustrated in Figs. 12, 13 and let. The use of the herein described invention, therefore, largely reduces the number of dies which must be kept on hand by the practitioner, and permits of the almost certain deviation from standard forms which is necessary where an artistically formed crown is tobe made to suit the exact shape required for any individual tooth which may be met with in practice.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that some details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim:

1. A die for forming tooth-crowns, comprising a member having a matrix formed thereon approximating the shape of a tooth end but having the marginal portions at all sides inclined outwardly to meet the top face of the die at an acute angle.

2. A die for forming tooth-crowns, comprising a member having a plurality of matrices formed thereon of varying sizes and shapes, each of said matrices approximating a tooth end but being of increased diameter and having the marginal portions thereof flared outwardly to meet the face of the die at an acute angle.

Signed at Chicago this 23d day of June LEON M. FARNUM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

